sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
echo "deb http://download.webmin.com/download/repository sarge contrib" | sudo tee -a /etc/apt/sources.list
wget http://www.webmin.com/jcameron-key.asc
sudo apt-key add jcameron-key.asc
sudo apt update
sudo apt install webmin -y